This invention relates to gravity feed tray droppers having rotary head tray dispensers. More specifically, this invention relates to a gravity feed tray dropper which may be quickly and accurately adjusted to any size, shape or lip thickness of trays whether the trays be paper, plastic or metal. The invention has particular utility in dispensing trays such as used in the frozen food packaging industry and will be described in this context.
Trays of frozen foods, such as vegetables, sauces, meat dishes, baked goods, pastries, and almost every other variety of food which is susceptible to pre-cooking and freezing is now customarily packaged in shallow draft trays, having perimeter flanges or lips, which can be stacked and fed either singularly or in multiples onto a food conveyor where the trays are filled and sealed. Because trays are made from various materials, and are made in virtually unlimited numbers of shapes and sizes, including circular, rectangular, and all variations inbetween, there has been a long felt need for a tray dropper which does not require a different dispensing head for each different size of tray.
Heretofore, rotary dispensing heads have been of the screw type, such as shown in prior art FIG. 1, wherein a screw thread S grips the lip L of a tray T between helical flights S1 and S2. It will be readily appreciated that the number of lip thicknesses which can be accommodated between flights of a particular screw thread is extremely limited. Accordingly, in order to change over from one type of tray to another type of tray, having a different lip thickness, it has been necessary to substitute a dispensing head having a screw thread of a different pitch. This, of course, requires that a wide range of dispensing heads be maintained in stock for changing over from one size tray to another size tray, and also involves considerable labor and down time in making these change overs. Additionally, it has been known for set-up men to wedge the flights of the helical screw threads apart or to hammer them together in order to avoid the down time required to replace the dispensing heads. This has resulted in uneven results, erratic dispensing and has been another cost factor in the utilization of this type of tray dropper.